Headrest support structure

Abstract

A headrest support having a hollow cylindrical shape and into which a headrest stay is inserted, is inserted into a bracket that has a hollow cylindrical shape and is fixed to a seat back frame. A protrusion, a tip end of which is a pivot center of the headrest support, formed such that a protrusion amount thereof increases in response to insertion of the headrest stay, is provided on an outer peripheral surface of this headrest support.

The invention claimed is: 
     
       1. A headrest support structure comprising:
 a headrest support having a hollow cylindrical shape, into which a headrest stay is inserted; and 
 a bracket having a hollow cylindrical shape that is fixed to a seat back frame, and into which the headrest support is inserted, wherein 
 the headrest support is pivotally supported with respect to the bracket, around a contact portion between a tip end of a protrusion provided on a seat front side of the headrest support and an inner peripheral surface of the bracket; 
 the protrusion is formed such that a protrusion amount thereof toward an outer peripheral side of the headrest support increases in response to insertion of the headrest stay; 
 a protruding bead, which is opposed to the protrusion, is formed on a seat rear side of the headrest support. 
 
     
     
       2. The headrest support structure according to  claim 1 , wherein
 the headrest support is formed to include two slits provided in parallel so as to sandwich the protrusion. 
 
     
     
       3. The headrest support structure according to  claim 1 , wherein a position of the tip end of the protrusion when the headrest stay is not inserted is a position in which the tip end of the protrusion does not contact the inner peripheral surface of the bracket when the headrest support is inserted into the bracket and the headrest stay is not inserted. 
     
     
       4. The headrest support structure according to  claim 1 , further comprising:
 an elastic member provided on the headrest support, the elastic member elastically supporting a headrest via the headrest stay. 
 
     
     
       5. A headrest support structure comprising:
 a headrest support having a hollow cylindrical shape, into which a headrest stay is inserted; and 
 a bracket having a hollow cylindrical shape that is fixed to a seat back frame, and into which the headrest support is inserted, wherein 
 the headrest support is pivotally supported with respect to the bracket, around a contact portion between a tip end of a protrusion provided on a seat front side of the headrest support and an inner peripheral surface of the bracket; 
 an inner peripheral surface of the headrest support when the headrest stay is not inserted locally bulges out toward an inner peripheral side of the headrest support, at a location where the protrusion is formed; 
 a protruding bead, which is opposed to the protrusion, is formed on a seat rear side of the headrest support. 
 
     
     
       6. The headrest support structure according to  claim 5 , wherein
 the headrest support is formed to include two slits provided in parallel so as to sandwich the protrusion. 
 
     
     
       7. The headrest support structure according to  claim 5 , wherein a position of the tip end of the protrusion when the headrest stay is not inserted is a position in which the tip end of the protrusion does not contact the inner peripheral surface of the bracket when the headrest support is inserted into the bracket and the headrest stay is not inserted. 
     
     
       8. The headrest support structure according to  claim 5 , further comprising:
 an elastic member provided on the headrest support, the elastic member elastically supporting a headrest via the headrest stay. 
 
     
     
       9. A headrest support structure comprising:
 a headrest support having a hollow cylindrical shape, into which a headrest stay is inserted; and 
 a bracket having a hollow cylindrical shape that is fixed to a seat back frame, and into which the headrest support is inserted, wherein 
 the headrest support is pivotally supported with respect to the bracket, around a contact portion between a tip end of a protrusion provided on a seat front side of the headrest support and an inner peripheral surface of the bracket; 
 the protrusion is formed such that a protrusion amount thereof toward an outer peripheral side of the headrest support increases in response to insertion of the headrest stay; 
 
       a protruding bead, which is opposed to the protrusion, is formed on a seat rear side of the headrest support,
 wherein the headrest support is formed to include two slits provided in parallel so as to sandwich the protrusion.